The Reporoa Caldera is located in the northern part of the Taupō-Reporoa Basin, which extends north-east from
Lake Taupō in the south to the
Waiotapu geothermal area, and whose southern features are distinct from the caldera. The long term lake was
Lake Huka which was destroyed in the 25,600 years ago
Oruanui eruption. After the Oruanui eruption there is evidence for a
Lake Reporoa temporary lake in the Reporoa Basin which has some uncertainty about its height at various times. This lake occupied up to of the basin impounding about of water. which temporarily flooded for no more than a week, some of the area of the former Lake Reporoa to above present sea level. but is now thought to be about 50,000 years older at 281 ± 21 ka
BP. and magnetic studies have been used to define the caldera to being north of the present Waikato River course in the Taupō-Reporoa Basin. A relative gravity low does exist south-west of the river and caldera in the Mihi area and has been called the Mihi volcanic depression, although there is presently no evidence of a related volcanic event. The Reporoa Caldera is associated with three geothermal fields. These are the active
Reporoa geothermal field in the caldera, the
Waiotapu geothermal area north of the caldera rim, and the Broadlands thermal area to the south. ==See also==